Urine interleukin‐1β in children with acute pyelonephritis and renal scarring

SUMMARY: Aim:  Acute pyelonephritis is a common infectious disease in children and can result in permanent renal damage. Interleukin (IL)-1β is an important inflammatory mediator that appears early during bacterial infection. This prospective study examined urine IL-1β levels in children with acute pyelonephritis documented by 99mTc-dimercaptosuccinic acid (DMSA) scan, and also evaluated whether this cytokine correlated with renal scarring. Methods:  A total of 75 children aged 1–121 months with a diagnosis of first-time febrile urinary tract infection (UTI) were studied. The following inflammatory markers were assessed: fever, white blood cell (WBC), neutrophil, C-reactive protein (CRP) and urine IL-1β. Urine samples were collected for IL-1β measurement by enzyme-linked immunosorbent assay before and after antibiotic treatment of the infection. Follow-up DMSA scan was performed at 6–12 months after the acute pyelonephritis to detect renal scarring. Twenty children with other febrile illnesses served as non-renal febrile controls. Results:  The 75 children were divided into acute pyelonephritis (n = 41) and lower UTI (n = 34) groups according to the findings of DMSA scans. Fever, WBC count, neutrophil count and CRP were significantly higher in the children with acute pyelonephritis than in those with lower UTI (all P < 0.001). The initial urine IL-1β levels of children with acute pyelonephritis were significantly higher when compared with lower UTI and non-renal febrile controls (P < 0.001). Urine IL-1β in children with acute pyelonephritis was positively correlated with fever, CRP, WBC, neutrophil and leucocyturia. Renal scarring was found in 12 (29.3%) of the 41 children with acute pyelonephritis. The mean age was significantly lower in the children with renal scarring compared with those without (P < 0.05). Conclusion:  These results have shown that urine IL-1β level may serve as a useful marker for the early detection of acute pyelonephritis in febrile children. Young children are at a risk of the development of renal scarring following acute pyelonephritis.